1
|
Garric S, Ratin M, Marie D, Foulon V, Probert I, Rodriguez F, Six C. Impaired photoacclimation in a kleptoplastidic dinoflagellate reveals physiological limits of early stages of endosymbiosis. Curr Biol 2024:S0960-9822(24)00743-7. [PMID: 38936366 DOI: 10.1016/j.cub.2024.05.066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2024] [Revised: 04/02/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024]
Abstract
Dinophysis dinoflagellates are predators of Mesodinium ciliates, from which they retain only the plastids of cryptophyte origin. The absence of nuclear photosynthetic cryptophyte genes in Dinophysis raises intriguing physiological and evolutionary questions regarding the functional dynamics of these temporary kleptoplastids within a foreign cellular environment. In an experimental setup including two light conditions, the comparative analysis with Mesodinium rubrum and the cryptophyte Teleaulax amphioxeia revealed that Dinophysis acuminata possessed a smaller and less dynamic functional photosynthetic antenna for green light, a function performed by phycoerythrin. We showed that the lack of the cryptophyte nucleus prevented the synthesis of the phycoerythrin α subunit, thereby hindering the formation of a complete phycoerythrin in Dinophysis. In particular, biochemical analyses showed that Dinophysis acuminata synthesized a poorly stable, incomplete phycoerythrin composed of chromophorylated β subunits, with impaired performance. We show that, consequently, a continuous supply of new plastids is crucial for growth and effective photoacclimation in this organism. Transcriptome analyses revealed that all examined strains of Dinophysis spp. have acquired the cryptophyte pebA and pebB genes through horizontal gene transfer, suggesting a potential ability to synthesize the phycobilin pigments bound to the cryptophyte phycoerythrin. By emphasizing that a potential long-term acquisition of the cryptophyte plastid relies on establishing genetic independence for essential functions such as light harvesting, this study highlights the intricate molecular challenges inherent in the enslavement of organelles and the processes involved in the diversification of photosynthetic organisms through endosymbiosis.
Collapse
Affiliation(s)
- Sarah Garric
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7144, Adaptation et Diversité en Milieu Marin, group Ecology of Marine Plankton, Station Biologique de Roscoff, Place Georges Teissier, Roscoff 29680, France
| | - Morgane Ratin
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7144, Adaptation et Diversité en Milieu Marin, group Ecology of Marine Plankton, Station Biologique de Roscoff, Place Georges Teissier, Roscoff 29680, France
| | - Dominique Marie
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7144, Adaptation et Diversité en Milieu Marin, group Ecology of Marine Plankton, Station Biologique de Roscoff, Place Georges Teissier, Roscoff 29680, France
| | - Valentin Foulon
- Centre National de la Recherche Scientifique, UMR 6285 Laboratoire des Sciences et Techniques de l'information de la Communication et de la Connaissance (Lab-STICC), Technopole Brest-Iroise, Brest 29238, France
| | - Ian Probert
- Sorbonne Université, FR 2424, Station Biologique de Roscoff, Place Georges Teissier, Roscoff 29680, France
| | - Francisco Rodriguez
- Centro oceanográfico de Vigo (IEO-CSIC), Subida a Radio Faro 50, Vigo 36390, Spain
| | - Christophe Six
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7144, Adaptation et Diversité en Milieu Marin, group Ecology of Marine Plankton, Station Biologique de Roscoff, Place Georges Teissier, Roscoff 29680, France.
| |
Collapse
|
2
|
Miyagishima SY. Taming the perils of photosynthesis by eukaryotes: constraints on endosymbiotic evolution in aquatic ecosystems. Commun Biol 2023; 6:1150. [PMID: 37952050 PMCID: PMC10640588 DOI: 10.1038/s42003-023-05544-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 11/03/2023] [Indexed: 11/14/2023] Open
Abstract
An ancestral eukaryote acquired photosynthesis by genetically integrating a cyanobacterial endosymbiont as the chloroplast. The chloroplast was then further integrated into many other eukaryotic lineages through secondary endosymbiotic events of unicellular eukaryotic algae. While photosynthesis enables autotrophy, it also generates reactive oxygen species that can cause oxidative stress. To mitigate the stress, photosynthetic eukaryotes employ various mechanisms, including regulating chloroplast light absorption and repairing or removing damaged chloroplasts by sensing light and photosynthetic status. Recent studies have shown that, besides algae and plants with innate chloroplasts, several lineages of numerous unicellular eukaryotes engage in acquired phototrophy by hosting algal endosymbionts or by transiently utilizing chloroplasts sequestrated from algal prey in aquatic ecosystems. In addition, it has become evident that unicellular organisms engaged in acquired phototrophy, as well as those that feed on algae, have also developed mechanisms to cope with photosynthetic oxidative stress. These mechanisms are limited but similar to those employed by algae and plants. Thus, there appear to be constraints on the evolution of those mechanisms, which likely began by incorporating photosynthetic cells before the establishment of chloroplasts by extending preexisting mechanisms to cope with oxidative stress originating from mitochondrial respiration and acquiring new mechanisms.
Collapse
Affiliation(s)
- Shin-Ya Miyagishima
- Department of Gene Function and Phenomics, National Institute of Genetics, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
- The Graduate University for Advanced Studies, SOKENDAI, 1111 Yata, Mishima, Shizuoka, 411-8540, Japan.
| |
Collapse
|
3
|
Christa G. Kleptoplasty. Curr Biol 2023; 33:R465-R467. [PMID: 37279674 DOI: 10.1016/j.cub.2023.03.036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Gregor Christa introduces kleptoplasty - the process by which heterotrophs steal chloroplasts from algae and incorporate them into their cytosol.
Collapse
Affiliation(s)
- Gregor Christa
- Institute for Zoology, University of Wuppertal, Wuppertal, Germany.
| |
Collapse
|
4
|
Moeller HV, Hsu V, Lepori-Bui M, Mesrop LY, Chinn C, Johnson MD. Prey type constrains growth and photosynthetic capacity of the kleptoplastidic ciliate Mesodinium chamaeleon (Ciliophora). JOURNAL OF PHYCOLOGY 2021; 57:916-930. [PMID: 33454988 DOI: 10.1111/jpy.13131] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 12/18/2020] [Accepted: 12/21/2020] [Indexed: 06/12/2023]
Abstract
Kleptoplastidic, or chloroplast-stealing, lineages offer insight into the process of acquiring photosynthesis. By quantifying the ability of these organisms to retain and use photosynthetic machinery from their prey, we can understand how intermediaries on the endosymbiosis pathway might have evolved regulatory and maintenance mechanisms. Here, we focus on a mixotrophic kleptoplastidic ciliate, Mesodinium chamaeleon, noteworthy for its ability to retain functional chloroplasts from at least half a dozen cryptophyte algal genera. We contrasted the performance of kleptoplastids from blue-green and red cryptophyte prey as a function of light level and feeding history. Our experiments showed that starved M. chamaeleon cells are able to maintain photosynthetic function for at least 2 weeks and that M. chamaeleon containing red plastids lost chlorophyll and electron transport capacity faster than those containing blue-green plastids. However, likely due to increased pigment content and photosynthetic rates in red plastids, M. chamaeleon had higher growth rates and more prolonged growth when feeding on red cryptophytes. For example, M. chamaeleon grew rapidly and extensively when fed the blue-green cryptophyte Chroomonas mesostigmatica, but this growth appeared to hinge on high levels of feeding supporting photosynthetic activity. In contrast, even starved M. chamaeleon containing red plastids from Rhodomonas salina could achieve high photosynthetic rates and extensive growth. Our findings show that plastid origin impacts the maintenance and magnitude of photosynthetic activity, though whether this is due to variation in ciliate control or gradual loss of plastid function in ingested prey cells remains unknown.
Collapse
Affiliation(s)
- Holly V Moeller
- Department of Ecology, Evolution, and Marine Biology, University of California - Santa Barbara, Santa Barbara, California, 93106, USA
| | - Veronica Hsu
- Department of Ecology, Evolution, and Marine Biology, University of California - Santa Barbara, Santa Barbara, California, 93106, USA
| | - Michelle Lepori-Bui
- Department of Ecology, Evolution, and Marine Biology, University of California - Santa Barbara, Santa Barbara, California, 93106, USA
| | - Lisa Y Mesrop
- Department of Ecology, Evolution, and Marine Biology, University of California - Santa Barbara, Santa Barbara, California, 93106, USA
| | - Cara Chinn
- Department of Ecology, Evolution, and Marine Biology, University of California - Santa Barbara, Santa Barbara, California, 93106, USA
| | - Matthew D Johnson
- Biology Department, Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, 02543, USA
| |
Collapse
|
5
|
Jeong HJ, Kang HC, Lim AS, Jang SH, Lee K, Lee SY, Ok JH, You JH, Kim JH, Lee KH, Park SA, Eom SH, Yoo YD, Kim KY. Feeding diverse prey as an excellent strategy of mixotrophic dinoflagellates for global dominance. SCIENCE ADVANCES 2021; 7:7/2/eabe4214. [PMID: 33523999 PMCID: PMC7793574 DOI: 10.1126/sciadv.abe4214] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/20/2020] [Accepted: 11/16/2020] [Indexed: 06/12/2023]
Abstract
Microalgae fuel food webs and biogeochemical cycles of key elements in the ocean. What determines microalgal dominance in the ocean is a long-standing question. Red tide distribution data (spanning 1990 to 2019) show that mixotrophic dinoflagellates, capable of photosynthesis and predation together, were responsible for ~40% of the species forming red tides globally. Counterintuitively, the species with low or moderate growth rates but diverse prey including diatoms caused red tides globally. The ability of these dinoflagellates to trade off growth for prey diversity is another genetic factor critical to formation of red tides across diverse ocean conditions. This finding has profound implications for explaining the global dominance of particular microalgae, their key eco-evolutionary strategy, and prediction of harmful red tide outbreaks.
Collapse
Affiliation(s)
- Hae Jin Jeong
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea.
| | - Hee Chang Kang
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea.
| | - An Suk Lim
- Division of Life Science and Plant Molecular Biology and Biotechnology Research Center, Gyeongsang National University, Jinju 52828, Korea
| | - Se Hyeon Jang
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Kitack Lee
- Division of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sung Yeon Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Jin Hee Ok
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Ji Hyun You
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Ji Hye Kim
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Kyung Ha Lee
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Sang Ah Park
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Se Hee Eom
- School of Earth and Environmental Sciences, Seoul National University, Seoul 08826, Korea
| | - Yeong Du Yoo
- Faculty of Marine Applied Biosciences, Kunsan National University, Gunsan 54150, Korea
| | - Kwang Young Kim
- Department of Oceanography, Chonnam National University, Gwangju, Korea
| |
Collapse
|
6
|
Díaz PA, Fernández-Pena C, Pérez-Santos I, Baldrich Á, Díaz M, Rodríguez F. Dinophysis Ehrenberg (Dinophyceae) in Southern Chile harbours red cryptophyte plastids from Rhodomonas/Storeatula clade. HARMFUL ALGAE 2020; 99:101907. [PMID: 33218433 DOI: 10.1016/j.hal.2020.101907] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 08/26/2020] [Accepted: 09/24/2020] [Indexed: 06/11/2023]
Abstract
Photosynthetic species of the dinoflagellate genus Dinophysis are known to retain temporary cryptophyte plastids of the Teleaulax/Plagioselmis/Geminigera clade after feeding the ciliate Mesodinium rubrum. In the present study, partial plastid 23S rDNA sequences were retrieved in Southern Chilean waters from oceanic (Los Lagos region), and fjord systems (Aysén region), in single cells of Dinophysis and accompanying organisms (the heliozoan Actinophrys cf. sol and tintinnid ciliates), identified by means of morphological discrimination under the light microscope. All plastid 23S rDNA sequences (n = 23) from Dinophysis spp. (Dinophysis acuta, D. caudata, D. tripos and D. subcircularis) belonged to cryptophytes from clade V (Rhinomonas, Rhodomonas and Storeatula), although they could not be identified at genus level. Moreover, five plastid sequences obtained from heliozoans (Actinophryida, tentatively identified as Actinophrys cf. sol), and tintinnid ciliates, grouped together with those cryptophyte sequences. In contrast, two additional sequences from tintinnids belonged to other taxa (chlorophytes and cyanobacteria). Overall, the present study represents the first time that red cryptophyte plastids outside of the Teleaulax/Plagioselmis/Geminigera clade dominate in wild photosynthetic Dinophysis spp. These findings suggest that either Dinophysis spp. are able to feed on other ciliate prey than Mesodinium and/or that cryptophyte plastids from clade V prevail in members of the M. rubrum species complex in the studied area.
Collapse
Affiliation(s)
- Patricio A Díaz
- Centro i~mar, Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile; CeBiB, Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile.
| | - Concepción Fernández-Pena
- Centro Oceanográfico de A Coruña, (IEO), Paseo Marítimo Alcalde Francisco Vázquez, 10, Coruña 15001, Spain
| | - Iván Pérez-Santos
- Centro i~mar, Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile; Centro de Investigación Oceanográfica COPAS Sur-Austral, Campus Concepción, Universidad de Concepción, Concepción 4030000, Chile
| | - Ángela Baldrich
- Centro i~mar, Universidad de Los Lagos, Casilla 557, Puerto Montt, Chile; Programa de Doctorado en Ciencias, mención Manejo y Conservación de Recursos Naturales, Universidad de Los Lagos, Puerto Montt, Chile
| | - Manuel Díaz
- Programa de Investigación Pesquera & Instituto de Acuicultura, Universidad Austral de Chile, Sede Puerto Montt, Chile
| | - Francisco Rodríguez
- Centro Oceanográfico de Vigo, Instituto Español de Oceanografía (IEO), Subida a Radio Faro 50, Vigo 36390, Spain
| |
Collapse
|
7
|
Fiorendino JM, Smith JL, Campbell L. Growth response of Dinophysis, Mesodinium, and Teleaulax cultures to temperature, irradiance, and salinity. HARMFUL ALGAE 2020; 98:101896. [PMID: 33129454 DOI: 10.1016/j.hal.2020.101896] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2020] [Revised: 08/21/2020] [Accepted: 08/21/2020] [Indexed: 06/11/2023]
Abstract
Mixotrophic Dinophysis species threaten human health and coastal economies through the production of toxins which cause diarrhetic shellfish poisoning (DSP) in humans. Novel blooms of Dinophysis acuminata and Dinophysis ovum have occurred in North American waters in recent decades, resulting in the closure of shellfish harvesting. Understanding the ecology of Dinophysis species and their prey is essential to predicting and mitigating the impact of blooms of these dinoflagellates. The growth response of two new isolates of Dinophysis species, one isolate of Mesodinium rubrum, and two strains of Teleaulax amphioxeia were evaluated at a range of temperature, salinity, and irradiance treatments to identify possible environmental drivers of Dinophysis blooms in the Gulf of Mexico. Results showed optimal growth of T. amphioxeia and M. rubrum at 24 °C, salinity 30 - 34, and irradiances between 300 and 400 µmol quanta m - 2s - 1. Optimal Dinophysis growth was observed at salinity 22 and temperatures between 18 and 24 °C. Mesodinium and both Dinophysis responded differently to experimental treatments, which may be due to the suitability of prey and different handling of kleptochloroplasts. Dinophysis bloom onset may be initiated by warming surface waters between winter and spring in the Gulf of Mexico. Toxin profiles for these two North American isolates were distinct; Dinophysis acuminata produced okadaic acid, dinophysistoxin-1, and pectenotoxin-2 while D. ovum produced only okadaic acid. Toxin per cell for D. ovum was two orders of magnitude greater than D. acuminata. Phylogenies based on the cox1 and cob genes did not distinguish these two Dinophysis species within the D. acuminata complex.
Collapse
Affiliation(s)
- James M Fiorendino
- Department of Oceanography, Texas A&M University, College Station, TX 77843, USA
| | - Juliette L Smith
- Virginia Institute of Marine Science, College of William & Mary, Gloucester Point, Virginia, 23062, USA
| | - Lisa Campbell
- Department of Oceanography, Texas A&M University, College Station, TX 77843, USA.
| |
Collapse
|
8
|
Cruz S, LeKieffre C, Cartaxana P, Hubas C, Thiney N, Jakobsen S, Escrig S, Jesus B, Kühl M, Calado R, Meibom A. Functional kleptoplasts intermediate incorporation of carbon and nitrogen in cells of the Sacoglossa sea slug Elysia viridis. Sci Rep 2020; 10:10548. [PMID: 32601288 PMCID: PMC7324368 DOI: 10.1038/s41598-020-66909-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2020] [Accepted: 05/26/2020] [Indexed: 01/16/2023] Open
Abstract
Some sacoglossan sea slugs incorporate intracellular functional algal chloroplasts, a process termed kleptoplasty. “Stolen” chloroplasts (kleptoplasts) can remain photosynthetically active up to several months, contributing to animal nutrition. Whether this contribution occurs by means of translocation of photosynthesis-derived metabolites from functional kleptoplasts to the animal host or by simple digestion of such organelles remains controversial. Imaging of 13C and 15N assimilation over a 12-h incubation period of Elysia viridis sea slugs showed a light-dependent incorporation of carbon and nitrogen, observed first in digestive tubules and followed by a rapid accumulation into chloroplast-free organs. Furthermore, this work revealed the presence of 13C-labeled long-chain fatty acids (FA) typical of marine invertebrates, such as arachidonic (20:4n-6) and adrenic (22:4n-6) acids. The time frame and level of 13C- and 15N-labeling in chloroplast-free organs indicate that photosynthesis-derived primary metabolites were made available to the host through functional kleptoplasts. The presence of specific 13C-labeled long-chain FA, absent from E. viridis algal food, indicates animal based-elongation using kleptoplast-derived FA precursors. Finally, carbon and nitrogen were incorporated in organs and tissues involved in reproductive functions (albumin gland and gonadal follicles), implying a putative role of kleptoplast photosynthesis in the reproductive fitness of the animal host.
Collapse
Affiliation(s)
- Sónia Cruz
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.
| | - Charlotte LeKieffre
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal.,UMR CNRS 6112 LPG-BIAF, Université d'Angers, 2 Boulevard Lavoisier, 49045, Angers, Cedex 1, France.,Cell & Plant Physiology Laboratory, University of Grenoble Alpes, CNRS, CEA, INRA, Grenoble, France
| | - Paulo Cartaxana
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Cédric Hubas
- Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, Station Marine de Concarneau, Place de la croix, 29900, Concarneau, France
| | - Najet Thiney
- Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles, CNRS, IRD, Station Marine de Concarneau, Place de la croix, 29900, Concarneau, France
| | - Sofie Jakobsen
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000, Helsingør, Denmark
| | - Stéphane Escrig
- Laboratory for Biological Geochemistry, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland
| | - Bruno Jesus
- Laboratoire Mer Molécules Santé, Faculté des Sciences et des Techniques, Université de Nantes, 44322, Nantes, France
| | - Michael Kühl
- Marine Biological Section, Department of Biology, University of Copenhagen, 3000, Helsingør, Denmark
| | - Ricardo Calado
- ECOMARE, CESAM - Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Campus Universitário de Santiago, 3810-193, Aveiro, Portugal
| | - Anders Meibom
- Laboratory for Biological Geochemistry, École Polytechnique Fédérale de Lausanne, 1015, Lausanne, Switzerland.,Center for Advanced Surface Analysis, Institute of Earth Sciences, University of Lausanne, 1015, Lausanne, Switzerland
| |
Collapse
|
9
|
Jauffrais T, LeKieffre C, Schweizer M, Jesus B, Metzger E, Geslin E. Response of a kleptoplastidic foraminifer to heterotrophic starvation: photosynthesis and lipid droplet biogenesis. FEMS Microbiol Ecol 2020; 95:5427914. [PMID: 30947330 DOI: 10.1093/femsec/fiz046] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/02/2019] [Indexed: 01/21/2023] Open
Abstract
The aim of this work is to document the complex nutritional strategy developed by kleptoplastic intertidal foraminifera. We study the mixotrophic ability of a common intertidal foraminifer, Elphidium williamsoni, by (i) investigating the phylogenetic identity of the foraminiferal kleptoplasts, (ii) following their oxygenic photosynthetic capacity and (iii) observing the modification in cellular ultrastructural features in response to photoautotrophic conditions. This was achieved by coupling molecular phylogenetic analyses and TEM observations with non-destructive measurements of kleptoplast O2 production over a 15-day experimental study. Results show that the studied E. williamsoni actively selected kleptoplasts mainly from pennate diatoms and had the ability to produce oxygen, up to 13.4 nmol O2 cell-1 d-1, from low to relatively high irradiance over at least 15 days. Ultrastructural features and photophysiological data showed significant differences over time, the number of lipid droplets, residual bodies and the dark respiration increased; whereas, the number of kleptoplasts decreased accompanied by a minor decrease of the photosynthetic rate. These observations suggest that in E. williamsoni kleptoplasts might provide extra carbon storage through lipid droplets synthesis and highlight the complexity of E. williamsoni feeding strategy and the necessity of further dedicated studies regarding mechanisms developed by kleptoplastidic foraminifera for carbon partitioning and storage.
Collapse
Affiliation(s)
- Thierry Jauffrais
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France.,Ifremer, RBE/LEAD, 101 Promenade Roger Laroque, 98897 Nouméa, New Caledonia, France
| | - Charlotte LeKieffre
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| | - Magali Schweizer
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| | - Bruno Jesus
- EA2160, Laboratoir Mer Molécules Santé, 2 rue de la Houssinière, Université de Nantes, 4433 Nantes Cedex 1, France
| | - Edouard Metzger
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| | - Emmanuelle Geslin
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d'Angers, 2 Boulevard Lavoisier, 49045 Angers CEDEX 1, France
| |
Collapse
|
10
|
Abstract
AbstractIn order to set a base line for the observation of planktonic community changes due to global change, protistan plankton sampling in combination with phycotoxin measurements and solid phase adsorption toxin tracking (SPATT) was performed in two bays of King George Island (KGI) in January 2013 and 2014. In addition, SPATT sampling was performed in Potter Cove during a one-year period from January 2014 until January 2015. Known toxigenic taxa were not firmly identified in plankton samples but there was microscopical evidence for background level presence of Dinophysis spp. in the area. This was consistent with environmental conditions during the sampling periods, especially strong mixing of the water column and low water temperatures that do not favor dinoflagellate proliferations. Due to the lack of significant abundance of thecate toxigenic dinoflagellate species in microplankton samples, no phycotoxins were found in net tow samples. In contrast, SPATT sampling revealed the presence of dissolved pectenotoxin-2 (PTX-2) and its hydrolyzed form PTX-2 seco acid in both bays and during the entire one-year sampling period. The presence of dissolved PTX in coastal waters of KGI is strong new evidence for the presence of PTX-producing species, i.e., dinoflagellates of the genus Dinophysis in the area. The presence of phycotoxins and their respective producers, even at the low background concentrations found in this study, may be the seed of possible proliferations of these species under changing environmental conditions. Furthermore, phycotoxins can be used as chemotaxonomic markers for a very specific group of plankton thus allowing to track the presence of this group over time.
Collapse
|
11
|
Jia Y, Gao H, Tong M, Anderson DM. Cell cycle regulation of the mixotrophic dinoflagellate Dinophysis acuminata: Growth, photosynthetic efficiency and toxin production. HARMFUL ALGAE 2019; 89:101672. [PMID: 31672228 PMCID: PMC6914227 DOI: 10.1016/j.hal.2019.101672] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 09/24/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
The mixotrophic dinoflagellate Dinophysis acuminata is a widely distributed diarrhetic shellfish poisoning (DSP) producer. Toxin variability of Dinophysis spp. has been well studied, but little is known of the manner in which toxin production is regulated throughout the cell cycle in these species, in part due to their mixotrophic characteristics. Therefore, an experiment was conducted to investigate cell cycle regulation of growth, photosynthetic efficiency, and toxin production in D. acuminata. First, a three-step synchronization approach, termed "starvation-feeding-dark", was used to achieve a high degree of synchrony of Dinophysis cells by starving the cells for 2 weeks, feeding them once, and then placing them in darkness for 58 h. The synchronized cells started DNA synthesis (S phase) 10 h after being released into the light, initiated G2 growth stage eight hours later, and completed mitosis (M phase) 2 h before lights were turned on. The toxin content of three dominant toxins, okadaic acid (OA), dinophysistoxin-1 (DTX1) and pectenotoxin-2 (PTX2), followed a common pattern of increasing in G1 phase, decreasing on entry into the S phase, then increasing again in S phase and decreasing in M phase during the diel cell cycle. Specific toxin production rates were positive throughout the G1 and S phases, but negative during the transition from G1 to S phase and late in M phase, the latter reflecting cell division. All toxins were initially induced by the light and positively correlated with the percentage of cells in S phase, indicating that biosynthesis of Dinophysis toxins might be under circadian regulation and be most active during DNA synthesis.
Collapse
Affiliation(s)
- Ying Jia
- Ocean College, Zhejiang University, Zhoushan, 316021, China
| | - Han Gao
- Ocean College, Zhejiang University, Zhoushan, 316021, China
| | - Mengmeng Tong
- Ocean College, Zhejiang University, Zhoushan, 316021, China.
| | - Donald M Anderson
- Biology Department, Woods Hole Oceanographic Institute, Woods Hole, MA, 02543, USA
| |
Collapse
|
12
|
García-Portela M, Reguera B, Ribera d'Alcalà M, Rodríguez F, Montresor M. Effects of small-scale turbulence on two species of Dinophysis. HARMFUL ALGAE 2019; 89:101654. [PMID: 31672223 DOI: 10.1016/j.hal.2019.101654] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2019] [Revised: 06/21/2019] [Accepted: 07/31/2019] [Indexed: 06/10/2023]
Abstract
Dinoflagellate species of Dinophysis, in particular D. acuminata and D. acuta, produce lipophilic toxins that pose a threat to human health when concentrated in shellfish and jeopardize shellfish exploitations in western Europe. In northwestern Iberia, D. acuminata has a long growing season, from spring to early autumn, and populations develop as soon as shallow stratification forms when the upwelling season begins. In contrast, D. acuta blooms in late summer, when the depth of the pycnocline is maximal and upwelling pulses are moderate. In situ observations on the hydrodynamic regimes during the two windows of opportunity for Dinophysis species led us to hypothesize that D. acuta should be more sensitive to turbulence than D. acuminata. To test this hypothesis, we studied the response of D. acuminata and D. acuta to three realistic turbulence levels low (LT), ε ≈ 10-6 m2 s-3; medium (MT), ε ≈ 10-5 m2 s-3 and high (HT), ε ≈ 10-4 m2 s-3generated by Turbogen, a highly reproducible, computer-controlled system. Cells of both species exposed to LT and MT grew at rates similar to the controls. Marked differences were found in the response to HT: D. acuminata grew slowly after an initial lag phase, whereas D. acuta cell numbers declined. Results from this study support the hypothesis that turbulence may play a role in shaping the spatio-temporal distribution of individual species of Dinophysis. We also hypothesize that, in addition to cell disturbance affecting division, sustained high shear generated by microturbulence may cause a decline in Dinophysis numbers due to decreased densities of ciliate prey.
Collapse
Affiliation(s)
- María García-Portela
- Harmful Microalgae Group (VGOHAB), Centro Oceanográfico de Vigo, IEO, Vigo, Spain.
| | - Beatriz Reguera
- Harmful Microalgae Group (VGOHAB), Centro Oceanográfico de Vigo, IEO, Vigo, Spain.
| | | | - Francisco Rodríguez
- Harmful Microalgae Group (VGOHAB), Centro Oceanográfico de Vigo, IEO, Vigo, Spain.
| | - Marina Montresor
- Department of Integrative Marine Ecology, Stazione Zoologica Anton Dohrn, Naples, Italy.
| |
Collapse
|
13
|
Cruaud P, Vigneron A, Fradette MS, Dorea CC, Culley AI, Rodriguez MJ, Charette SJ. Annual Protist Community Dynamics in a Freshwater Ecosystem Undergoing Contrasted Climatic Conditions: The Saint-Charles River (Canada). Front Microbiol 2019; 10:2359. [PMID: 31681222 PMCID: PMC6805768 DOI: 10.3389/fmicb.2019.02359] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 09/27/2019] [Indexed: 11/23/2022] Open
Abstract
Protists are key stone components of aquatic ecosystems, sustaining primary productivity and aquatic food webs. However, their diversity, ecology and structuring factors shaping their temporal distribution remain strongly misunderstood in freshwaters. Using high-throughput sequencing on water samples collected over 16 different months (including two summer and two winter periods), combined with geochemical measurements and climate monitoring, we comprehensively determined the pico- and nanoeukaryotic community composition and dynamics in a Canadian river undergoing prolonged ice-cover winters. Our analysis revealed a large protist diversity in this fluctuating ecosystem and clear seasonal patterns demonstrating a direct and/or indirect selective role of abiotic factors, such as water temperature or nitrogen concentrations, in structuring the eukaryotic microbial community. Nonetheless, our results also revealed that primary productivity, predatory as well as parasitism lifestyles, inferred from fine phylogenetic placements, remained potentially present over the annual cycle, despite the large seasonal fluctuations and the remodeling of the community composition under ice. In addition, potential interplays with the bacterial community composition were identified supporting a possible contribution of the bacterial community to the temporal dynamics of the protist community structure. Our results illustrate the complexity of the eukaryotic microbial community and provide a substantive and useful dataset to better understand the global freshwater ecosystem functioning.
Collapse
Affiliation(s)
- Perrine Cruaud
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, QC, Canada.,CRAD, Université Laval, Québec City, QC, Canada
| | - Adrien Vigneron
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, QC, Canada.,Centre D'Études Nordiques, Université Laval, Québec City, QC, Canada.,Département de Biologie, Université Laval, Québec City, QC, Canada
| | - Marie-Stéphanie Fradette
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, QC, Canada.,CRAD, Université Laval, Québec City, QC, Canada
| | - Caetano C Dorea
- Department of Civil Engineering, University of Victoria, Victoria, BC, Canada
| | - Alexander I Culley
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, QC, Canada.,Groupe de Recherche en Ecologie Buccale, Faculté de Médecine Dentaire, Université Laval, Québec City, QC, Canada
| | - Manuel J Rodriguez
- CRAD, Université Laval, Québec City, QC, Canada.,École Supérieure D'aménagement du Territoire et de Développement Régional (ESAD), Université Laval, Québec City, QC, Canada
| | - Steve J Charette
- Institut de Biologie Intégrative et des Systèmes, Université Laval, Québec City, QC, Canada.,Département de Biochimie, de Microbiologie et de Bio-Informatique, Faculté des Sciences et de Génie, Université Laval, Québec City, QC, Canada.,Centre de Recherche de l'Institut Universitaire de Cardiologie et de Pneumologie de Québec, Québec City, QC, Canada
| |
Collapse
|
14
|
Wilken S, Yung CCM, Hamilton M, Hoadley K, Nzongo J, Eckmann C, Corrochano-Luque M, Poirier C, Worden AZ. The need to account for cell biology in characterizing predatory mixotrophs in aquatic environments. Philos Trans R Soc Lond B Biol Sci 2019; 374:20190090. [PMID: 31587652 DOI: 10.1098/rstb.2019.0090] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Photosynthesis in eukaryotes first arose through phagocytotic processes wherein an engulfed cyanobacterium was not digested, but instead became a permanent organelle. Other photosynthetic lineages then arose when eukaryotic cells engulfed other already photosynthetic eukaryotic cells. Some of the resulting lineages subsequently lost their ability for phagocytosis, while many others maintained the ability to do both processes. These mixotrophic taxa have more complicated ecological roles, in that they are both primary producers and consumers that can shift more towards producing the organic matter that forms the base of aquatic food chains, or towards respiring and releasing CO2. We still have much to learn about which taxa are predatory mixotrophs as well as about the physiological consequences of this lifestyle, in part, because much of the diversity of unicellular eukaryotes in aquatic ecosystems remains uncultured. Here, we discuss existing methods for studying predatory mixotrophs, their individual biases, and how single-cell approaches can enhance knowledge of these important taxa. The question remains what the gold standard should be for assigning a mixotrophic status to ill-characterized or uncultured taxa-a status that dictates how organisms are incorporated into carbon cycle models and how their ecosystem roles may shift in future lakes and oceans. This article is part of a discussion meeting issue 'Single cell ecology'.
Collapse
Affiliation(s)
- Susanne Wilken
- Department of Freshwater and Marine Ecology, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 1090GE Amsterdam, Noord-Holland, The Netherlands.,Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Department of Marine Biology and Oceanography, Institute of Marine Sciences (ICM)-CSIC, 08003 Barcelona, Catalunya, Spain
| | - Charmaine C M Yung
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Ocean EcoSystems Biology Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Schleswig-Holstein, Germany
| | - Maria Hamilton
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Division of Physical and Biological Sciences, UC Santa Cruz, Santa Cruz, CA 95064, USA
| | - Kenneth Hoadley
- Ocean EcoSystems Biology Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Schleswig-Holstein, Germany
| | - Juliana Nzongo
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Division of Physical and Biological Sciences, UC Santa Cruz, Santa Cruz, CA 95064, USA
| | - Charlotte Eckmann
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Division of Physical and Biological Sciences, UC Santa Cruz, Santa Cruz, CA 95064, USA
| | | | - Camille Poirier
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Ocean EcoSystems Biology Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Schleswig-Holstein, Germany
| | - Alexandra Z Worden
- Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA.,Ocean EcoSystems Biology Unit, GEOMAR Helmholtz Centre for Ocean Research Kiel, 24148 Kiel, Schleswig-Holstein, Germany.,Division of Physical and Biological Sciences, UC Santa Cruz, Santa Cruz, CA 95064, USA
| |
Collapse
|
15
|
Gavelis GS, Gile GH. How did cyanobacteria first embark on the path to becoming plastids?: lessons from protist symbioses. FEMS Microbiol Lett 2019; 365:5079637. [PMID: 30165400 DOI: 10.1093/femsle/fny209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Accepted: 08/23/2018] [Indexed: 12/13/2022] Open
Abstract
Symbioses between phototrophs and heterotrophs (a.k.a 'photosymbioses') are extremely common, and range from loose and temporary associations to obligate and highly specialized forms. In the history of life, the most transformative was the 'primary endosymbiosis,' wherein a cyanobacterium was engulfed by a eukaryote and became genetically integrated as a heritable photosynthetic organelle, or plastid. By allowing the rise of algae and plants, this event dramatically altered the biosphere, but its remote origin over one billion years ago has obscured the sequence of events leading to its establishment. Here, we review the genetic, physiological and developmental hurdles involved in early primary endosymbiosis. Since we cannot travel back in time to witness these evolutionary junctures, we will draw on examples of unicellular eukaryotes (protists) spanning diverse modes of photosymbiosis. We also review experimental approaches that could be used to recreate aspects of early primary endosymbiosis on a human timescale.
Collapse
Affiliation(s)
- Gregory S Gavelis
- School of Life Sciences, Arizona State University, Room 611, Life Science Tower E, 427 E, Tyler Mall, Tempe, AZ 85287, USA
| | - Gillian H Gile
- School of Life Sciences, Arizona State University, Room 611, Life Science Tower E, 427 E, Tyler Mall, Tempe, AZ 85287, USA
| |
Collapse
|
16
|
García-Portela M, Riobó P, Reguera B, Garrido JL, Blanco J, Rodríguez F. Comparative ecophysiology of Dinophysis acuminata and D. acuta (DINOPHYCEAE, DINOPHYSIALES): effect of light intensity and quality on growth, cellular toxin content, and photosynthesis. JOURNAL OF PHYCOLOGY 2018; 54:899-917. [PMID: 30298602 DOI: 10.1111/jpy.12794] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2018] [Accepted: 09/24/2018] [Indexed: 06/08/2023]
Abstract
Dinoflagellates of the genus Dinophysis are the most persistent producers of lipophilic shellfish toxins in Western Europe. Their mixotrophic nutrition requires a food chain of cryptophytes and plastid-bearing ciliates for sustained growth and photosynthesis. In this study, cultures of D. acuminata and D. acuta, their ciliate prey Mesodinium rubrum and the cryptophyte, Teleaulax amphioxeia, were subject to three experimental settings to study their physiological response to different combinations of light intensity and quality. Growth rates, pigment analyses (HPLC), photosynthetic parameters (PAM-fluorometry), and cellular toxin content (LC-MS) were determined. Specific differences in photosynthetic parameters were observed in Dinophysis exposed to different photon fluxes (10-650 μmol photons · m-2 · s-1 ), light quality (white, blue and green), and shifts in light regime. Dinophysis acuta was more susceptible to photodamage under high light intensities (370-650 μmol photons · m-2 · s-1 ) than D. acuminata but survived better with low light (10 μmol photons · m-2 · s-1 ) and to a prolonged period (28 d) of darkness. Mesodinium rubrum and T. amphioxeia showed their maximal growth rate and yield under white and high light whereas Dinophysis seemed better adapted to grow under green and blue light. Toxin analyses in Dinophysis showed maximal toxin per cell under high light after prey depletion at the late exponential-plateau phase. Changes observed in photosynthetic light curves of D. acuminata cultures after shifting light conditions from low intensity-blue light to high intensity-white light seemed compatible with photoacclimation in this species. Results obtained here are discussed in relation to different spatiotemporal distributions observed in field populations of D. acuminata and D. acuta in northwestern Iberia.
Collapse
Affiliation(s)
- María García-Portela
- Spanish Institute of Oceanography (IEO), Oceanographic Centre of Vigo, 36390 Vigo, Pontevedra, Spain
| | - Pilar Riobó
- Marine Research Institute (IIM-CSIC), 36208 Vigo, Pontevedra, Spain
| | - Beatriz Reguera
- Spanish Institute of Oceanography (IEO), Oceanographic Centre of Vigo, 36390 Vigo, Pontevedra, Spain
| | | | - Juan Blanco
- Marine Research Centre (CIMA), 36620 Vilanova de Arousa, Pontevedra, Spain
| | - Francisco Rodríguez
- Spanish Institute of Oceanography (IEO), Oceanographic Centre of Vigo, 36390 Vigo, Pontevedra, Spain
| |
Collapse
|
17
|
Impact of Dinophysis acuminata Feeding Mesodinium rubrum on Nutrient Dynamics and Bacterial Composition in a Microcosm. Toxins (Basel) 2018; 10:toxins10110443. [PMID: 30380714 PMCID: PMC6266072 DOI: 10.3390/toxins10110443] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 10/25/2018] [Accepted: 10/25/2018] [Indexed: 02/02/2023] Open
Abstract
The development of Dinophysis populations, producers of diarrhetic shellfish toxins, has been attributed to both abiotic (e.g., water column stratification) and biotic (prey availability) factors. An important process to consider is mixotrophy of the Dinophysis species, which is an intensive feeding of the Mesodinium species for nutrients and a benefit from kleptochloroplasts. During the feeding process, the nutritional status in the environment changes due to the preference of Mesodinium and/or Dinophysis for different nutrients, prey cell debris generated by sloppy feeding, and their degradation by micro-organisms changes. However, there is little knowledge about the role of the bacterial community during the co-occurrence of Mesodinium and Dinophysis and how they directly or indirectly interact with the mixotrophs. In this study, laboratory experiments were performed to characterize the environmental changes including those of the prey present, the bacterial communities, and the ambient dissolved nutrients during the co-occurrence of Mesodinium rubrum and Dinophysis acuminata. The results showed that, during the incubation of the ciliate prey Mesodinium with its predator Dinophysis, available dissolved nitrogen significantly shifted from nitrate to ammonium especially when the population of M. rubrum decayed. Growth phases of Dinophysis and Mesodinium greatly affected the structure and composition of the bacterial community. These changes could be mainly explained by both the changes of the nutrient status and the activity of Dinophysis cells. Dinophysis feeding activity also accelerated the decline of M. rubrum and contamination of cultures with okadaic acid, dinophysistoxin-1, and pectenotoxin-2, but their influence on the prokaryotic communities was limited to the rare taxa (<0.1%) fraction. This suggests that the interaction between D. acuminata and bacteria is species-specific and takes place intracellularly or in the phycosphere. Moreover, a majority of the dominant bacterial taxa in our cultures may also exhibit a metabolic flexibility and, thus, be unaffected taxonomically by changes within the Mesodinium-Dinophysis culture system.
Collapse
|
18
|
Kleptoplast photosynthesis is nutritionally relevant in the sea slug Elysia viridis. Sci Rep 2017; 7:7714. [PMID: 28798379 PMCID: PMC5552801 DOI: 10.1038/s41598-017-08002-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 07/06/2017] [Indexed: 12/02/2022] Open
Abstract
Several sacoglossan sea slug species feed on macroalgae and incorporate chloroplasts into tubular cells of their digestive diverticula. We investigated the role of the “stolen” chloroplasts (kleptoplasts) in the nutrition of the sea slug Elysia viridis and assessed how their abundance, distribution and photosynthetic activity were affected by light and starvation. Elysia viridis individuals feeding on the macroalga Codium tomentosum were compared with starved specimens kept in dark and low light conditions. A combination of variable Chl a fluorescence and hyperspectral imaging, and HPLC pigment analysis was used to evaluate the spatial and temporal variability of photopigments and of the photosynthetic capacity of kleptoplasts. We show increased loss of weight and body length in dark-starved E. viridis as compared to low light-starved sea slugs. A more pronounced decrease in kleptoplast abundance and lower photosynthetic electron transport rates were observed in dark-starved sea slugs than in low light-starved animals. This study presents strong evidence of the importance of kleptoplast photosynthesis for the nutrition of E. viridis in periods of food scarcity. Deprived of photosynthates, E. viridis could accelerate the breakdown of kleptoplasts in the dark to satisfy its’ energy requirements.
Collapse
|
19
|
Drumm K, Liebst-Olsen M, Daugbjerg N, Moestrup Ø, Hansen PJ. Effects of irradiance and prey deprivation on growth, cell carbon and photosynthetic activity of the freshwater kleptoplastidic dinoflagellate Nusuttodinium (= Gymnodinium) aeruginosum (Dinophyceae). PLoS One 2017; 12:e0181751. [PMID: 28763480 PMCID: PMC5538715 DOI: 10.1371/journal.pone.0181751] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Accepted: 07/06/2017] [Indexed: 12/03/2022] Open
Abstract
The freshwater dinoflagellate Nusuttodinium aeruginosum lacks permanent chloroplasts. Rather it sequesters chloroplasts as well as other cell organelles, like mitochondria and nuclei, from ingested cryptophyte prey. In the present study, growth rates, cell production and photosynthesis were measured at seven irradiances, ranging from 10 to 140 μmol photons m-2s-1, when fed the cryptophyte Chroomonas sp. Growth rates were positively influenced by irradiance and increased from 0.025 d-1 at 10 μmol photons m-2s-1 to maximum growth rates of ~0.3 d-1 at irradiances ≥ 40 μmol photons m-2s-1. Similarly, photosynthesis ranged from 1.84 to 36.9 pg C cell-1 h-1 at 10 and 140 μmol photons m-2s-1, respectively. The highest rates of photosynthesis in N. aeruginosum only corresponded to ~25% of its own cell carbon content and estimated biomass production. The measured rates of photosynthesis could not explain the observed growth rates at high irradiances. Cultures of N. aeruginosum subjected to prey starvation were able to survive for at least 27 days in the light. The sequestered chloroplasts maintained their photosynthetic activity during the entire period of starvation, during which the population underwent 4 cell divisions. This indicates that N. aeruginosum has some control of the chloroplasts, which may be able to replicate. In conclusion, N. aeruginosum seems to be in an early stage of chloroplast acquisition with some control of its ingested chloroplasts.
Collapse
Affiliation(s)
- Kirstine Drumm
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
- * E-mail:
| | - Mette Liebst-Olsen
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Niels Daugbjerg
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Øjvind Moestrup
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Per Juel Hansen
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
20
|
Rusterholz PM, Hansen PJ, Daugbjerg N. Evolutionary transition towards permanent chloroplasts? - Division of kleptochloroplasts in starved cells of two species of Dinophysis (Dinophyceae). PLoS One 2017; 12:e0177512. [PMID: 28493958 PMCID: PMC5426790 DOI: 10.1371/journal.pone.0177512] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 04/29/2017] [Indexed: 12/04/2022] Open
Abstract
Species within the marine toxic dinoflagellate genus Dinophysis are phagotrophic organisms that exploit chloroplasts (kleptochloroplasts) from other protists to perform photosynthesis. Dinophysis spp. acquire the kleptochloroplasts from the ciliate Mesodinium rubrum, which in turn acquires the chloroplasts from a unique clade of cryptophytes. Dinophysis spp. digest the prey nuclei and all other cell organelles upon ingestion (except the kleptochloroplasts) and they are therefore believed to constantly acquire new chloroplasts as the populations grow. Previous studies have, however, indicated that Dinophysis can keep the kleptochloroplasts active during long term starvation and are able to produce photosynthetic pigments when exposed to prey starvation. This indicates a considerable control over the kleptochloroplasts and the ability of Dinophysis to replicate its kleptochloroplasts was therefore re-investigated in detail in this study. The kleptochloroplasts of Dinophysis acuta and Dinophysis acuminata were analyzed using confocal microscopy and 3D bioimaging software during long term starvation experiments. The cell concentrations were monitored to confirm cell divisions and samples were withdrawn each time a doubling had occurred. The results show direct evidence of kleptochloroplastidic division and that the decreases in total kleptochloroplast volume, number of kleptochloroplasts and number of kleptochloroplast centers were not caused by dilution due to cell divisions. This is the first report of division of kleptochloroplasts in any protist without the associated prey nuclei. This indicates that Dinophysis spp. may be in a transitional phase towards possessing permanent chloroplasts, which thereby potentially makes it a key organism to understand the evolution of phototrophic protists.
Collapse
Affiliation(s)
| | - Per Juel Hansen
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Niels Daugbjerg
- Marine Biological Section, Department of Biology, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
21
|
Jauffrais T, Jesus B, Méléder V, Geslin E. Functional xanthophyll cycle and pigment content of a kleptoplastic benthic foraminifer: Haynesina germanica. PLoS One 2017; 12:e0172678. [PMID: 28231315 PMCID: PMC5322967 DOI: 10.1371/journal.pone.0172678] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Accepted: 02/08/2017] [Indexed: 11/19/2022] Open
Abstract
Some shallow water benthic foraminifera are able to retain functional chloroplasts (kleptoplasts) from their food source, i.e. diatoms. Here we assessed the functionality of the kleptoplast xanthophyll cycle (XC, i.e. the main diatom short-term photo-regulation mechanism) and we surveyed Haynesina germanica kleptoplast pigment composition over time and at different light regimes. Six common diatom lipophilic pigments were detected, two chlorophylls (Chl a, Chl c) and four carotenoids (fucoxanthin and by-products, diadinoxanthin, diatoxanthin and β-carotene), the same pigment profile as the diatom species frequently isolated at the sampling site. The xanthophyll cycle (XC) was functional with kleptoplast diatoxanthin (DT) content increase with concomitant diadinoxanthin (DD) decrease after short term light exposure. DT/(DT+DD) and DT/DD ratios increased significantly in specimens exposed to low light and high light in comparison to specimens maintained in the dark. Specimens placed in very low light after the light treatments reverted to values close to the initial ones, suggesting that H. germanica XC is functional. A functional XC is an indication of H. germanica kleptoplasts capacity for short-term photo-protection from photo-oxidative damages caused by excess of light. Furthermore, the pigment survey suggests that H. germanica preserved some chloroplasts over a longer time than others and that pigment content is influenced by previous light history. Finally, the current study highlighted seasonal differences, with higher pigment contents in winter specimens (27.35 ± 1.30 ng cell-1) and lower in summer specimens (6.08 ± 1.21 ng cell-1), a quantitative and qualitative composition suggesting light acclimation to low or high light availability, according to the season.
Collapse
Affiliation(s)
- Thierry Jauffrais
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d’Angers, Angers, France
- * E-mail:
| | - Bruno Jesus
- EA2160, Laboratoire Mer Molécules Santé, Université de Nantes, Nantes, France
- BioISI–Biosystems & Integrative Sciences Institute, Campo Grande University of Lisboa, Faculty of Sciences, Lisboa, Portugal
| | - Vona Méléder
- EA2160, Laboratoire Mer Molécules Santé, Université de Nantes, Nantes, France
| | - Emmanuelle Geslin
- UMR CNRS 6112 LPG-BIAF, Bio-Indicateurs Actuels et Fossiles, Université d’Angers, Angers, France
| |
Collapse
|